check on your fuse box and see if there is an open port, there may even be one that marked power seat. Then you will have to run a hot wire to the place you want to install the seat. You can probably get away with a body ground on the bolt to the same seat.

If you have to make a harness for it, then Summit Racing has all of the GM OEM connectors for great prices. I have made over 50 harnesses for my trucks, and they are the same thing the dealer sells to you for about $50! They are manufactured by PICO